Keep burning out condensers

[BioTex]

I was able to attempt to start my 345 for the first time in decades.
New cap, rotor, wires, plugs.
After filling the fuel bowl, and checking things over, I hit the key switch. I must say that I was extremely happy to hear the starter crank over.

I hooked up my induction timing light to get ready to time it, and noticed no flash while cranking. I probed the coil + with a test light, and it was full bright. I also measured 12 volts while cranking, and with the key in run position.

I have a known good 12Volt externally resisted coil. No spark. I pulled the cap, and verified the rotor was spinning, and I had 12V at the points, as well as the negative side of the coil while cranking.

So I figure the condenser is bad, as it was an old one. I changed it out with another used one I had, and cranked again. The strobe flashed about 5 times and quit.

Since I have 3 brand new condensers on the shelf, I figure I'll try it one more time with a new one. The engine ran perfectly (after I timed it). Revved perfectly, idled perfectly. 55psi oil pressure, no exhaust leaks or any wierd sounds. Just the purr... Then she died.

So here is what I need to know.

On the + side of the coil are two wires factory molded together. A black one and a white one. The white is to ignition switch, and has that funny insulation around it telling me that it is the resistance wire. The black I have hooked up to the I on my remote Ford style coil. You see, it used to go to the R on the old starter solonoid.

Should I leave that black wire off the I terminal?
Am I correct in running a 12V coil? Is it supposed to be a 6 volt coil?

Seems to me that the coil should get 12 volts while cranking, and 6 during run. Isn't that the reason for the resistance wire?

Since I didn't check the resistance of that wire, perhaps I should install a new ballast resistor and do away with the wire...

Anyways, I could really use some help here and I'm sure I left out some stuff, so please aske me what you need to know, and I'll be standing by.

PS. my internet was down all day. Someone cut a fiber optic cable, and it affected 3 counties. So I haven been able to do any searching yet. I'm hoping to get a quick fix before the day is over.

Edit: Just had a thought. If I was overcharging, that would do it. I went out and checked and I have 12 volts on the sense wire at the alternator, so I know that doesn't prove it's not overcharging, but it helps. Man, I hate to be so close, and can't finish.

[BioTex]

I think I have it figured out.

I went out and put my meter on the coil + and it reads battery voltage with the key in the run position. This must be what's burning up the condensers.
Shouldn't the resistor wire be reducing the voltage in the run position?

Would an internal resisted coil be the easy solution, or should I buy an external ballast resistor?

[jauringer]

"I think I have it figured out.

The two wires molded together are probably supposed to hook into a ballast resistor. The wire I'm thinking is a resistor wire must not be.
I went out and put my meter on the coil + and it reads battery voltage with the key in the run position. This must be what's burning up the condensers.

Would an internal resisted coil be the easy solution, or should I buy a ballast resistor?"
You don't want both wires running through a resistor as you want a full 12v at start up. Just run the ignition wire to a ballast resistor and then to the + side of the coil. The other wire from the "R" terminal should be hooked directly to the coil.


Edit: Also considering the wires are still merged together, it would seem that it would still be the OEM resisted wire. My OEM ignition wire was brown and had a cloth type loom around it. It was easy to identify as the resisted ignition wire.
Jason

[Greg R]

On the + side of the coil are two wires factory molded together. A black one and a white one. The white is to ignition switch, and has that funny insulation around it telling me that it is the resistance wire. The black I have hooked up to the I on my remote Ford style coil. You see, it used to go to the R on the old starter solonoid.

That is the correct hook up.

Ignition 101: During "Run" mode, the feed to the coil is resisted with a ballast resistor that limits current, not voltage. With no load you may see full voltage in and out, under load is when you will see a reduced voltage. A plumbing analogy would be a flow limiting device for compressed air or water like a restsrictor that doesn't reduce pressure but does reduce flow. No flow or use, equal pressure upstream and downstream. Open a valve or turn something and the flow restriction will also make a pressure drop. It's what a compression leak down tester is based on.

During "Start" mode the resistance feed is bypassed, so you will have both connections at the coil feed or somewhere in the feed to it.

Does the coil get warm? Try checking it's resistance as soon as the engine dies. I've seen old coils test okay, and then fail after a short run. It may be the original resistance feed is failing as you suggest. Try a new ballast resistor in temporary fashion and see if the engine will keep running as long as you need it.

A condensor test is as follows: A few ohms resistance followed by a quick rise to infinity when you apply the test leads of an ohm meter.

Double check your distributor connections and verify the point gap or dwell. Points can be tricky and tightening the binder screws on them can inadvertently change the gap.

[Jay Tabor]

you got some bad condensors, and the dist. isnt grounded very well, clean the plate where the condensor mounts to, and make sure the strap holding the cond is clean and tight to the cond.. and screwed down tightly to the dist. point plate.

[BioTex]

Originally Posted by Greg R

That is the correct hook up.

Ignition 101: During "Run" mode, the feed to the coil is resisted with a ballast resistor that limits current, not voltage. With no load you may see full voltage in and out, under load is when you will see a reduced voltage. A plumbing analogy would be a flow limiting device for compressed air or water like a restsrictor that doesn't reduce pressure but does reduce flow. No flow or use, equal pressure upstream and downstream. Open a valve or turn something and the flow restriction will also make a pressure drop. It's what a compression leak down tester is based on.

During "Start" mode the resistance feed is bypassed, so you will have both connections at the coil feed or somewhere in the feed to it.

Does the coil get warm? Try checking it's resistance as soon as the engine dies. I've seen old coils test okay, and then fail after a short run. It may be the original resistance feed is failing as you suggest. Try a new ballast resistor in temporary fashion and see if the engine will keep running as long as you need it.

A condensor test is as follows: A few ohms resistance followed by a quick rise to infinity when you apply the test leads of an ohm meter.

Double check your distributor connections and verify the point gap or dwell. Points can be tricky and tightening the binder screws on them can inadvertently change the gap.

Good to know I at least had it hooked up correctly. After all, I had every wire out, and cleaned everything up. I traced out every wire and labeled them when I reinstalled the harness. I'll have to go back to my notes to see what the resistor wire ohmed out at. It wasn't spot on, but was fairly close, so I went with it. Wonder if that was a mistake.

The coild doen't get even warm, and was new. I hooked it up to an AMC engine, and it worked just fine. I hooked up an IH coil, and it also burned out a condenser.

Originally Posted by Jay Tabor

you got some bad condensors, and the dist. isnt grounded very well, clean the plate where the condensor mounts to, and make sure the strap holding the cond is clean and tight to the cond.. and screwed down tightly to the dist. point plate.

Jay, From the very beginning, I added an extra ground to the tub. I hooked up somer alligator clips to the metal vacuum line to the alternator ground. I have the battery - going to the head, I have the tub grounded to the ground lug on the back of the alternator.

I was planning to add some more grounds, but felt that as long as the engine was grounded to the neg. battery post, and the starter turned, then the ground was good enough to fire the engine. I will double check the distributor grounding in the AM.

I should probably pull the hold down clamp and sand the housing where it touches. Maybe add a wire under the bolt head and give it a better ground. Sure won't hurt.

I did add a ground wire to the remote solonoid mounting base, but haven't hooked it up yet. Started getting too cold out.

If I get her started again tomorrow, I'll check the output of the alternator and see if it is overcharging.

[Comanche Scott]

I've seen this happen a few times with new points.
Sometimes new points have a rust inhibitor, that also inhibits a good flow of current. Since the condenser is in parallel, it may be absorbing too much current, causing it to fail.

If you haven't already done this, it might be worth a try to pull the points, spray them down with brake or electric cleaner, and run a piece of crokus cloth across the tips.
Another thing is to check the pigtail lead between the advance plate and the base plate of the distributor. If it is loose, or the strands are breaking, it can cause the condenser to fail.

Hope tomorrow goes smoother!

[Bill Bennett]

If you can get the 'run' voltage closer to 8.5 when the engine is running, that may solve the condenser issues. There should be a 'resistance' built into the ignition circuit to drop the voltage from the 12.+ volts at the battery to the lower 'running' voltage.

[Greg R]

How you know the condenser is burning out?
They typically handle several hundred volts, not current; and only charge and discharge with the point action.

I've never seen one fail, but they are made so cheap it probably does happen and good insurance to change them.

One way to verify voltage is rig a light on the + terminal of the coil. Put it where you can see it. If it goes out when the engine dies, then you know without a doubt it's a power problem. Also rig a light on the - terminal of the coil. It should flicker when running. If it goes out when the engine dies, and the + side lite is still on, you have a coil problem or an intermittent short in the primary circuit or stuck points. It if remains a steady on and the thing dies, then you have a primary side problem in the distributor with an open path to ground or points failing to close.

[Thomas]

---If you're certain you're burning up condensers I would swing toward a coil/ignition switch test. testing procedures found in almost any service manual for starting. It's even more simple than acquiring a FSM/FRSM, which I know has been mentioned before. All it takes in this case, is a trip to the library and pulling a Chitlons manual off the shelf, then turning to the troubleshooting section. Then on the way home, dial that portable game/music player and borrowing/buying a cheap multimeter from a friend. An engine analyzer w/tach & dwell as well as volts, ohms & diode tester (even a $12 one) is a must if you have points. Then, if you're lacking the second most basic (FSM/FRSM being first) of tools, you can make a make-shift test light made of alligator clips w/in-line 12v (158/168/194 bulb works great) and follow the instructions.

---Possible your ignition switch is damaged?

---As for a condenser, they should show near, if not infinite, resistance when tested with an ohm meter.